Various mechanisms exist for resuming a system from a sleep mode. The Advanced Configuration Power Interface (ACPI) defines sleep modes for existing systems. The current specification for ACPI may be found at www*acpi*info. Note that periods have been replaced with asterisks in URLs identified in this document to avoid inadvertent hyperlinks. Existing systems typically implement S3 sleep mode with the basic input output system (BIOS) and store the replay script in ACPI non-volatile store (NVS), which is really just reserved memory, along with the wake vector, or the address within the operating system (OS) to return control. Attacks against ACPI Source Language (ASL) code and infrastructure have been noted that could put the integrity of the system at risk.